The present invention relates to an inspection and analysis technique for use in an electronic component such as semiconductor devices including a semiconductor memory, a microprocessor, a semiconductor laser, etc., and as a magnetic head; and, more particularly, to a technique of machining (or processing) and observation of the cross section of a sample by an ion beam.
High manufacturing yield is an important requisite for the manufacture of electronic components, such as semiconductor devices, e.g., semiconductor memories typically represented as dynamic random access memories (DRAMs), microprocessors and semiconductor lasers, and magnetic heads. This is because a fall of the product yield is directly linked to lower corporate profits. Therefore, early detection of and countermeasures to deal with defects, foreign matter and poor machining are indeed major issues to be resolved.
For example, electronic component manufacturing plants have put much effort on discovery of defects by careful inspection, and analysis of their causes. In actual electronic component manufacturing processes using wafers, the wafers in the course of machining are examined, the cause of abnormalities such as defects and foreign matter in circuit patterns is investigated, and methods to deal with them are considered.
Typically, high resolution scanning electron microscope (hereinafter abbreviated as SEM) is used to observe an abnormal spot on a sample. A composite FIB (Focused Ion Beam)-SEM is also currently used. The FIB-SEM machine irradiates FIB to form a square hole into a desired spot, and allows one to observe its cross section by SEM.
For instance, Japanese Patent Application Laid-Open No. 2002-150990 discloses a square hole for the observation and analysis of a defect or a foreign matter, in which an aperture is formed by using an FIB in the vicinity of an abnormal spot in a sample and cross section of the square hole is observed by SEM.
Moreover, International Patent Application Publication No. WO99/05506 discloses a technique for extracting a micro sample for TEM observation from a bulk sample by using an FIB and a probe.
Also, one example of ion beam processor related techniques in Japanese Patent Application Laid-Open No. 2-062039 discloses that reactive gas cylinders of plural kinds of gases are connected to an ionization chamber through valves, such that a reactive gas corresponding to the material of a layer to be processed of a sample is switched and supplied when a reactive etching process is executed locally in an ion beam irradiation unit.
In addition, Japanese Patent Application Laid-Open No. 2004-40129 discloses a technique for filling up a processed hole of a wafer from which a micro sample is extracted and returning the wafer to the production line.